Morfometria da microbacia hidrográfica do Ribeirão Faxinal Botucatu - SP e alterações em suas áreas de biomassa no período de 1972 a 2000
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Data
2004-12-08
Autores
Santos, André Ferreira dos [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
A preservação dos ambientes naturais é atualmente, uma preocupação mundial. Com isto, pode-se dizer que a avaliação dentro de uma região geográfica (microbacia), seja um dos primeiros passos para se obter informações do quanto um ambiente apresenta-se degradado. Neste sentido, o presente estudo objetivou-se em analisar as características morfométricas, bem como determinar possíveis alterações, mediante auxilio de técnicas fotointerpretativas, em áreas de biomassa, como (fragmento de matas, savanas, culturas agrícolas, reflorestamentos, mata ciliar), no período de 1972 a 2000, na microbacia do Ribeirão Faxinal, Botucatu-SP. A delimitação dos divisores de água, a rede de drenagem, área e as coberturas vegetais estudadas, foram obtidas com o auxílio de fotografias aéreas verticais, pertencentes à cobertura aerofotogramétrica do Estado de São Paulo, nos anos de 1972 e 2000, em escala nominal aproximada 1:25. 000 e 1:30. 000 respectivamente, e através das cartas topográficas na escala 1:50. 000 com curvas de nível eqüidistantes de 20 metros, editadas pelo IBGE em 1968. Os parâmetros morfométricos mostraram que a microbacia esta inserida em uma área de 5.170 ha, apresentando declividade média de 4,0 %, em relevo suave ondulado. Quantos aos outros índices, forma e densidade de drenagem, pode-se inferir que a microbacia não é propensa a ocorrência de enchentes. A pastagem foi a principal ocupação da área, representando 59, 6% da área total (1972) e 59,98% (2000), ou seja, mais da metade da área. As áreas ocupadas com a cultura do café apresentaram os maiores decréscimos de ocorrência na microbacia, ou seja, decresceram em 5,68%, uma vez que em 1972 era de 5,95%, passando a ocupar apenas 0,27 % em 2000...
Presently the preservation of natural resources is a mundial preoccupation. For this one geographic area is the most places for to get information for environmental degradation. This study aimed at morph metric characterization, as to define possible changes in biomass cover ( forest, fragment forest, agricultural cultures, reforestation, savannas), through photo interpretative methods, from 1972 to 2000, from the small watershed Faxinal river, in the city of Botucatu - SP. The water divisor delimitation, the drainage net, the area and the vegetables cover was got by vertical aerials photographs belonging to the aerophotogrametic covering of the State of Sao Paulo, in the years 1972 and 2000, in approximate 1:25.000 and 1:30.000 nominal scale, and topographical charts 1:50.000 scale, with contour lines 20 meters equidistant, of IBGE, were used. The study analyzed of the parameters of morfometric of small watershed, was the areas of this 5.170 ha, whit 4,0 % of declivity, showed of that micro basin in classificated in waving pleasant raise. The watershed was classified in the 4a order river ramification. Whit another morfometric index of form and drenage showed that micro basin presented low danger of plodding due its format. The results of occurred changes in the soil occupation, in 1972 and 2000, following conclusions. The pasture was the predominant land use, occupation 59,60% in 1972 and 59,98% in 2000. The areas of coffee culture was showing this significance reduction, presented decrease of 5,8%. In 1972 this areas represent 5,95% of the areas, and 2000 this area represent 0,27%. The natural forest occupations, with fragment forest and savannas, showing this cover reduction, however the ciliar forest haved a valuable increase, because of the preserve the natures resources. But the areas of reforestation and another cultivation showing a littlies increase.
Presently the preservation of natural resources is a mundial preoccupation. For this one geographic area is the most places for to get information for environmental degradation. This study aimed at morph metric characterization, as to define possible changes in biomass cover ( forest, fragment forest, agricultural cultures, reforestation, savannas), through photo interpretative methods, from 1972 to 2000, from the small watershed Faxinal river, in the city of Botucatu - SP. The water divisor delimitation, the drainage net, the area and the vegetables cover was got by vertical aerials photographs belonging to the aerophotogrametic covering of the State of Sao Paulo, in the years 1972 and 2000, in approximate 1:25.000 and 1:30.000 nominal scale, and topographical charts 1:50.000 scale, with contour lines 20 meters equidistant, of IBGE, were used. The study analyzed of the parameters of morfometric of small watershed, was the areas of this 5.170 ha, whit 4,0 % of declivity, showed of that micro basin in classificated in waving pleasant raise. The watershed was classified in the 4a order river ramification. Whit another morfometric index of form and drenage showed that micro basin presented low danger of plodding due its format. The results of occurred changes in the soil occupation, in 1972 and 2000, following conclusions. The pasture was the predominant land use, occupation 59,60% in 1972 and 59,98% in 2000. The areas of coffee culture was showing this significance reduction, presented decrease of 5,8%. In 1972 this areas represent 5,95% of the areas, and 2000 this area represent 0,27%. The natural forest occupations, with fragment forest and savannas, showing this cover reduction, however the ciliar forest haved a valuable increase, because of the preserve the natures resources. But the areas of reforestation and another cultivation showing a littlies increase.
Descrição
Palavras-chave
Bacias hidrograficas - Botucatu (SP), Geomorfologia, Solo - Uso, Fotografias aéreas, Small watershed, Analysis morfometric, Soil occupations
Como citar
SANTOS, André Ferreira dos. Morfometria da microbacia hidrográfica do Ribeirão Faxinal Botucatu - SP e alterações em suas áreas de biomassa no período de 1972 a 2000. 2004. viii, 59 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Ciências Agronômicas, 2004.